The present disclosure relates to an image processing apparatus and method, and more particularly, to an image processing apparatus and method capable of improving encoding efficiency in encoding an image.
To meet a need for the higher quality of an image, there has been an attempt to improve the resolution of an image from that of a standard image to an image for a high definition television (HDTV) and a 4 k×2 k image for a digital cinema. Further, an increase in a high bit depth of an image is in progress. For example, some imaging devices can acquire an image with a bit depth of 12 bits or more. Moreover, some liquid display devices can express gray scales of 10 bits or more.
On the other hand, image encoding schemes, such as the moving picture experts group-2 (MPEG-2) for a video and the joint photographic experts group (JPEG) for a still image, can process only an image with a bit depth of 8 bits or less. However, image encoding schemes, such as high profile of the advanced video coding (AVC) or JPEG 2000, can process an image with a bit depth of 8 bits or more.
For example, there has been suggested a method of efficiently encoding an image with a high bit depth by executing an encoding process with a two-step configuration of a bit depth conversion process and a reverse bit depth conversion process (for example, see “Preview on Encoding of High Bit Depth Image Using Bit Depth Conversion Process” by Ken Ito, Kogi Bando, Seishi Takamura, Kazoto Kamikura, Yoshiyuki Yashima, Institute of Electronics, Information, Communication Engineers General Conference s-5, 2009).